In general, a diamond film should have a crystalline structure close to a single crystal in order that it may be used as a material for electronic devices. As one of approaches for manufacturing a textured diamond film, it has been suggested that a diamond film can be grown under the usual diamond film CVD conditions, by subjecting chemical vapor deposition on a substrate after applying a negative bias to the substrate to induce diamond nucleation and then, by removing the negative bias applied to the substrate (see: X. Jiang et al., Phys. Rev. B, 50:8402(1994)). Also, Wolter et al. proposed an in-situ process for manufacturing a textured diamond film which comprises the following steps: forming an interfacial layer on a silicone substrate via carburization before carrying out the diamond nucleation, applying a negative bias, and allowing the nuclei thus formed to grow under a specified growth condition of a single orientation (see: S. D. Wolter, Appl. Phys. Lett., 62:1215(1993)).
However, more than 90% of the nuclei formed by the application of a negative bias have been revealed to have a random orientation without a heteroepitaxy relation with a substrate. In order to overcome this problem, it is essential to maintain the growth rate of nuclei having the heteroepitaxy relation more faster than that of nuclei of random orientation, so that the diamond film can be of a highly textured surface. Therefore, the prior art method has proven to be less satisfactory in a sense that deposition of a film with a thickness of more than 5 .mu.m is essentially accompanied, to obtain a diamond film with a heteroepitaxy.
Moreover, since nuclei at the similar orientation to the heteroepitaxy are not discriminated from nuclei with the heteroepitaxy in terms of the growth rates, film grains of the nuclei do not accomplish a complete heteroepitaxy, and have a disagreed azimuth which in turn provides a crystalline structure different from a single crystal due to the presence of tilt. Actually, only below 50% of grains have an orientation when a diamond film is manufactured according to the above method.
Stoner et al. reported that the higher nucleation density can be obtained in a relatively short period when a strong plasma is formed near a substrate and a strong negative bias is applied to the substrate (see: B. R. Stoner et al., J. Mater. Res., 7:257(1992)). Also, Shigesato et al. proposed that the amount of hydrogen and the temperature of electron in a plasma around a substrate may be increased by applying a negative bias to the substrate and such a change in the plasma may play an important role of increasing the diamond nucleation density (see: Y. Shigesato et al., Appl. Phys. Letter, 63:314(1993)).
However, the conventional methods for manufacturing a diamond film has revealed a shortcoming that only the surface of a substrate can be contacted with a plasma, since a substrate is placed outside of the plasma or the surface of the substrate is made to contact with the plasma. Moreover, even though the substrate is inserted to the inside of the plasma, the said problem cannot be solved, since the substrate support of the CVD apparatus is much larger than the surface of the substrate.